MECHANISM OF CHAPERONE MEDIATED PROTEIN FOLDING

我们研究的长期目标是了解蛋白质是如何有效的 折叠是在复杂的细胞内环境中完成的。我们是 特别感兴趣的是了解分子伴侣如何改变 蛋白质折叠反应的本质，以及分子的鸡尾酒 伴侣蛋白有助于确定可以折叠成 特定的有机体。了解如何高效地完成折叠 在体内可能会有重要的实际好处。例如，这样的研究 可能有助于更好地理解广谱的分子基础 涉及错误折叠或堆积的各种疾病 囊性纤维化、α1抗胰蛋白酶缺乏症等聚集蛋白 和基于Prion的脑病，以及允许更有效的 生产用于研究和商业目的的蛋白质。 目前的研究将集中在所谓的“伴侣”家族。 环状分子伴侣。伴侣蛋白形成了一个无处不在的 丰富的蛋白质家族，其成员在 在原核生物和真核生物中协助折叠。最新研究 提供有关大肠杆菌的结构和反应循环的丰富数据 伴侣蛋白GroEL及其辅助伴侣蛋白GroEs。这些研究表明， GroEL介导的折叠通过多轮结合和释放进行 非天然多肽，而蛋白质折叠通常是由 并可能在蛋白质保持隔离的情况下完成 GroEL在Groes下的中央空洞。利用这一能力 将GroEL-Groes介导的蛋白质折叠反应分解为特定的蛋白质折叠反应. 定义的步骤，我们将调查GroEL如何使用ATP的能量 帮助蛋白质折叠的水解物。我们还将使用各种生化手段 和生物物理方法，包括溶液结合研究和X射线 结晶学，以表征GroEL如何识别未折叠的蛋白质。 我们的具体目标是：(1)调查隔离的影响 GroEL-Groes复合体中的多肽位于其折叠路径上。(2) 探讨多肽环的作用机制及其功能意义 在伴侣蛋白介导的折叠反应中释放和重新结合。(3) 生物化学表征GroEL如何识别未折叠的底物。(4) 研究GroEL识别多肽的结构基础。

The long term goal of our research is to understand how efficient protein folding is achieved in the complex intracellular milieu. We are particularly interested in understanding how molecular chaperones alter the nature of protein folding reactions, and how the cocktail of molecular chaperones helps determine the spectrum of proteins that can fold in a particular organism. Knowledge of how efficient folding is accomplished in vivo could have important practical benefits. For example, such studies could lead to a better understanding of the molecular basis of a wide variety of diseases involving either misfolding or the accumulation of aggregated proteins such as Cystic Fibrosis, alpha1-Antitrypsin Deficiency and Prion based encephalopathies, as well as allow for the more efficient production of proteins for research and commercial purposes. The present studies will focus on the so called "chaperonin" family of ring-shaped molecular chaperones. The chaperonins form a ubiquitous and abundant family of proteins whose members play an essential role in assisting folding in both prokaryotes and eukaryotes. Recent studies provide a wealth of data on the structure and reaction cycle of the E. coli chaperonin GroEL and its co-chaperonin GroES. These studies establish that GroEL mediated folding proceeds by multiple round of binding and release of non-native polypeptides, and that protein folding is generally initiated and potentially completed while a protein remains sequestered within the GroEL central cavity under GroES. Taking advantage of the ability to dissect a GroEL-GroES mediated protein folding reaction into specific well- defined steps, we will investigate how GroEL uses the energy of ATP hydrolysis to assist protein folding. We will also use various biochemical and biophysical approaches, including solution binding studies and X-ray crystallography, to characterize how GroEL recognizes unfolded proteins. Our specific aims are to: (1) Investigate the effect of sequestering a polypeptide within a GroEL-GroES complexes on its folding pathway. (2) Examine the mechanism and functional significance of cycles of polypeptide release and rebinding during a chaperonin-mediated folding reaction. (3) Biochemically characterize how GroEL recognizes unfolded substrates. (4) Examine the structural basis of polypeptide recognition by GroEL.